9SKJ

Polysaccharide co-polymerase FepE open 8 subunit complex

Summary for 9SKJ

• Entry DOI: 10.2210/pdb9skj/pdb
• Related: 9SKI 9SKK 9SKL
• EMDB information: 54966 54969
• Descriptor: Ferric enterobactin transport protein FepE (1 entity in total)
• Functional Keywords: membrane protein, enzyme, polysaccharide, co-polymerase
• Biological source: Escherichia coli K-12
• Total number of polymer chains: 8
• Total formula weight: 352235.38

Authors

Wiseman, B.,Hogbom, M. (deposition date: 2025-09-02, release date: 2026-05-27)

Primary citation

Wiseman, B.,Widmalm, G.,Hogbom, M.
Structural Basis of Lipopolysaccharide O-Antigen Chain Length Modality.
Res, 9:1276-1276, 2026

PubMed Abstract: Lipopolysaccharides are important components of the gram-negative bacterial cell envelope that are involved in immune evasion and act as a protective barrier. Employing cryo-electron microscopy, we resolved the structure and dynamics of FepE, the copolymerase component of the Wzy-dependent pathway, responsible for the length modulation of very long O-antigen molecules. Comparison of the interior volumes of related copolymerases' periplasmic domains with the volume of hydrated sugars suggests that the size of the periplasmic domain controls the length of the O-antigen, implying that polysaccharide chain polymerization occurs inside the copolymerase periplasmic domain. Moreover, we show the opening of the FepE complex as well as other large mechanistically relevant movements. The opening of the complex presents an attractive corridor for the release of completed polysaccharide chains.

PubMed: 42131584
DOI: 10.34133/research.1276

Experimental method

ELECTRON MICROSCOPY (3.1 Å)